Bacterial Vaginosis: Symptoms, Treatment and Recurrence
Medically Reviewed by Dr. Pedro Yelamo Vera, MD
Licensed Physician No. 484814280 · Official Medical College of Bizkaia (Spain)Last reviewed: 31 October 2026
Bacterial vaginosis causes thin discharge with a fishy smell. How it differs from thrush, which treatment works in Spain, pregnancy and why it comes back.
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Dr. Pedro Yelamo Vera is an independent, bilingual GP licensed in Spain. Book a 15-minute video consultation in English or Spanish for €50, with a private electronic prescription issued under Spanish law when clinically appropriate.
Bacterial vaginosis (BV) is a common change in the normal balance of bacteria in the vagina. It often causes thin, grey-white discharge with a fishy smell, mainly after sex. About half of people have no symptoms. It is not an STI, though sex can trigger it. Antibiotics treat it, and in Spain they need a prescription.
- The typical sign is thin, watery, grey-white discharge with a strong fishy smell.
- BV is not an STI, but a new partner, douching and perfumed products make it more likely.
- Treatment is an antibiotic as tablets, gel or cream. In Spain these need a prescription.
- It often comes back within months. Longer treatment helps if it keeps returning.
- In pregnancy, tell your doctor or midwife about any change in discharge.
Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).
For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.
What are the symptoms of bacterial vaginosis?
The NHS says about half of people with BV have no symptoms. When they appear, the most common are:
- Discharge with a strong fishy smell, often worse after sex.
- Discharge that is thin and watery, and grey or white. Mayo Clinic adds that it can look greenish.
- Some people have itching or burning when they pee.
In Spain it is called vaginosis bacteriana.
Is it BV, thrush or an STI?
These three can feel alike, which is why a check matters.
- BV: thin grey-white discharge and a fishy smell.
- Thrush (candidiasis): intense itching and soreness, with a thick white discharge that does not usually smell. See our yeast infection page.
- An STI such as chlamydia, gonorrhoea or trichomonas can also change your discharge. Bleeding after sex or pain low in the tummy can be a sign of an STI or a pelvic infection.
Mayo Clinic advises a check if you treated yourself for thrush and still have symptoms, or if you have a new partner.
What causes BV, and how is it caught?
BV happens when "good" lactobacillus bacteria drop and other bacteria grow too much. The NHS says it is not an STI. But sex can trigger it or pass it on to someone with a vagina. Your risk is higher with:
- a new partner or more than one partner;
- an intrauterine device (IUD, or coil);
- douching, vaginal washes or deodorants;
- perfumed soaps, bubble bath or scented products;
- smoking.
How is bacterial vaginosis diagnosed?
A doctor asks about your symptoms and may examine you. They often take a swab (exudado vaginal) to confirm BV and rule out an STI. Mayo Clinic notes that a vaginal pH of 4.5 or higher is a sign of BV. In Spain you can see your GP (médico de familia), a gynaecologist or a private clinic for this.
What is the treatment for bacterial vaginosis?
BV is treated with an antibiotic. Mayo Clinic lists these options:
- Metronidazole (metronidazol), as tablets or a vaginal gel.
- Clindamycin (clindamicina), as a vaginal cream, capsules or pessaries.
- Tinidazole or secnidazole, also used in the US. Which medicines are sold varies by country.
In Spain, the UK and the US, metronidazole and clindamycin need a prescription. See our guide to which medicines need a prescription in Spain. UK guidance notes that vaginal clindamycin cream can weaken condoms.
Ask about alcohol. Mayo Clinic advises none during metronidazole and for a day after. Some UK guidance advises a longer gap. Follow the leaflet in your box and your doctor's advice.
Do pharmacy gels or probiotics cure BV?
Not reliably. Pharmacies sell gels that aim to restore the normal acid level of the vagina. They are not antibiotics. UK guidance lists one of these as licensed for BV and notes that another is not licensed for treatment. Mayo Clinic says probiotics are not recommended as a treatment. If symptoms last, see a doctor rather than trying product after product.
Unusual discharge, a fishy smell, or BV that keeps coming back?
You can book a private video visit with a GP licensed in Spain, in English or Spanish. He goes through your symptoms, tells you if you need a swab or STI tests, and talks you through treatment.
Does my partner need treatment too?
Current advice from Mayo Clinic and UK guidance says male partners usually do not need treatment. A female partner may need a check and treatment if she has symptoms.
This may change. A trial in the New England Journal of Medicine treated male partners with tablets plus a cream on the penis. BV came back in 35% of women whose partner was treated, against 63% when he was not. A later review of six trials found no clear overall benefit, and none from tablets alone. Ask a sexual health doctor if BV keeps returning with the same partner.
Why does BV keep coming back, and how can I prevent it?
Mayo Clinic says BV often returns within 3 to 12 months, even after the right treatment. The NHS says that if you get BV more than four times a year, a doctor may suggest a vaginal antibiotic gel used for a few months. These steps lower the risk:
- Wash the genital area with water and plain soap. Showers are better than baths.
- Do not douche or use vaginal washes, sprays or deodorants.
- Avoid perfumed bubble bath and scented products.
- Use condoms and clean sex toys after each use.
- Stop smoking.
Is bacterial vaginosis a risk in pregnancy?
The NHS says BV causes no problems in most pregnancies. There is a small chance of early birth or miscarriage. If your discharge changes while pregnant, speak to your doctor or midwife (matrona). Some antibiotics are safe in pregnancy, and your doctor will choose one that suits you. UK guidance advises a repeat test about a month later.
When should you see a doctor?
- You have symptoms for the first time, or they differ from before.
- You have a new partner, or you may have an STI.
- You are pregnant.
- Thrush treatment did not help.
- BV keeps coming back.
See a doctor today if you have pain low in your tummy, pain deep inside during sex, or bleeding between periods or after sex. These can be signs of pelvic inflammatory disease, which needs prompt treatment.
Call 112 or go to urgencias if tummy pain is severe or sudden, or comes with heavy bleeding, a high fever, fainting or feeling very unwell.
BV mainly affects women of childbearing age. A young girl with vaginal discharge should always see a doctor. The doctor looks for common causes and, as child-protection guidance asks, also checks that she is safe.
Talking it through with a doctor by video
Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:
- Ask about your discharge, smell, itching, your periods and any chance of pregnancy.
- Talk through your sexual health in private, and whether you need STI tests.
- Explain whether this sounds like BV, thrush or something else.
- Agree a plan for treatment and prevention, and tell you if you need a swab or an exam in person.
He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.
A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.
See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.
This guide is general information. It does not replace a consultation with your doctor.
Frequently asked questions
Is bacterial vaginosis an STI?
No. It is not classed as a sexually transmitted infection, but sex can trigger it or pass it between people with a vagina. A new partner raises the risk.
Can bacterial vaginosis go away on its own?
It sometimes settles, and people without symptoms usually do not need treatment. If you have symptoms or are pregnant, see a doctor, because antibiotics work well.
Can I buy BV treatment over the counter in Spain?
The antibiotics for BV, metronidazole and clindamycin, need a prescription in Spain. Pharmacy gels that aim to restore vaginal pH are not antibiotics.
Does my male partner need treatment?
Usually not, under current UK and US advice. One trial found that treating male partners with tablets and a skin cream cut recurrence, so guidance may change. Ask your doctor.
Why does BV keep coming back?
Recurrence is common. Mayo Clinic says BV often returns within 3 to 12 months, even after the right treatment. If it returns often, longer treatment can help.
Is BV dangerous in pregnancy?
Most pregnancies are not affected, but there is a small chance of problems such as early birth. If your discharge changes while pregnant, speak to your doctor or midwife.
Sources
- NHS: Bacterial vaginosis
- Mayo Clinic: Bacterial vaginosis, diagnosis and treatment
- NHS Scotland (BASHH-based guideline): Bacterial vaginosis
- Vodstrcil et al.: Male-partner treatment to prevent recurrence of BV (NEJM)
- Pacheco Vieira et al.: Male partner treatment for BV, meta-analysis
Related guides
Medical Citations & Sources
This content is written and reviewed by a licensed physician with reference to the following official health authorities.
